Convertible sofa bed mechanisms are in common use today particularly in boats, hotels, and homes where floor space is at a premium. Such products permit a single piece of furniture to serve different purposes during different periods of the day. A particularly successful convertible sofa bed mechanism has been sold for many years by the assignee of this application, Castro Convertible Corporation. The basic structure and operation of that mechanism is described and disclosed in U.S. Pat. No. 3,284,812. A slightly modified and updated version of the mechanism is also disclosed in U.S. Pat. No. 3,654,642.
The mechanism of the two above-described patents, as manufactured and sold by Castro Convertible Corporation, has been found to be very successful in use and operation. The mechanism is extremely durable and economical to manufacture.
Despite the success of such mechanisms, it has been found that the edge of the mattress or loose bedclothing on the mattress supported in the mechanism can sometimes become caught or pinched in the mechanism as it is folded. This could interfere with the folding operation of the mechanism or damage the mattress or bedclothing.
It is an object of the present invention to provide an improved folding bed mechanism which reduces the possibility of interference between the mechanism and the mattress or bedclothing thereon.
Another object of the present invention is to provide a compact folding bed mechanism of relatively high strength and automatic operation.
Yet another object of the present invention is to provide a folding bed mechanism which is relatively simple to operate and to manufacture.
In accordance with an aspect of the present invention a convertible sofa is provided which includes a frame and a folding bed mechanism mounted on the frame to swing into and out of the frame between folded and extended position. The mechanism includes a plurality of bed sections which are pivotally connected in series and consists of a support or head section located generally within the frame, an intermediate section pivotally connected to the support section, a center section pivotally connected to the intermediate section, and a foot section pivotally connected to the center section. A linkage arrangement is operatively connected between these sections to permit the sections to be pivoted relative to each other between the extended position wherein the sections are linearly aligned and a folded position wherein the foot section extends in a substantially horizontal plane parallel to and above the intermediate sections with the center section extending substantially vertically between the intermediate and foot sections. The linkage mechanism includes means which allows the folded foot, center and intermediate sections to move into and downwardly in the frame adjacent the support section to define the closed position of the convertible sofa.
The mechanism also includes a spring biased support bar pivotally connected to the frame and locking means pivotally connected to the intermediate section for locking the intermediate, center and foot sections in the extended position. A push linkage assembly is connected between the locking means and the spring biased support bar to apply a force to the bar against the bias of the spring to release the mechanism and allow it to be folded into the sofa frame. The push linkage assembly includes a first link pivotally connected at one end to the locking means and pivotally connected at its other end to a connector link which is in turn pivotally connected to the intermediate section of the folding bed mechanism. The connector link is also pivotally connected to a third link which is in turn pivotally connected to the intermediate section and to the support bar. As a result of this arrangement, movement of the locking mechanism during movement of the foot and center sections to the folded position pivots the connector link and third link against the bias of the support arm to allow the folded over foot, center and intermediate sections to move into and downwardly in the frame. In addition, the multilink push assembly allows the links to remain close to the intermediate section during folding of the bed, out of the way of the mattress and any bedclothing thereon.